Bair Scott
Georgia Institute of Technology, Center for High-Pressure Rheology, George W. Woodruff School of Mechanical Engineering, Atlanta, GA, 30332-0405, USA.
Sci Rep. 2022 Mar 1;12(1):3422. doi: 10.1038/s41598-022-07470-3.
In the classical approach to elastohydrodynamic lubrication (EHL) a single parameter, the pressure-viscosity coefficient, quantifies the isothermal pressure dependence of the viscosity for use in prediction of film thickness. Many definitions are in current use. Progress toward a successful definition of this property has been hampered by the refusal of those working in classical EHL to acknowledge the existence of accurate measurements of the piezoviscous effect that have existed for nearly a century. The Hamrock and Dowson pressure-viscosity coefficient at high temperature requires knowledge of the piezoviscous response at pressures which exceed the inlet pressure and may exceed the Hertz pressure. The definition of pressure-viscosity coefficient and the assumed equation of state must limit the use of the classical formulas, including Hamrock and Dowson, to liquids with high Newtonian limit and to low temperature. Given that this problem has existed for at least fifty years without resolution, it is reasonable to conclude that there is no definition of pressure-viscosity coefficient that will quantify the piezoviscous response for an analytical calculation of EHL film thickness at temperatures above ambient.
在弹性流体动力润滑（EHL）的经典方法中，一个单一参数——压力 - 粘度系数，用于量化粘度的等温压力依赖性，以预测膜厚。目前有许多种定义在使用。在成功定义这一特性方面所取得的进展一直受到阻碍，原因是经典EHL领域的研究人员拒绝承认存在已近一个世纪的准确的压粘效应测量结果。高温下的哈姆罗克和道森压力 - 粘度系数需要了解在超过入口压力且可能超过赫兹压力的压力下的压粘响应。压力 - 粘度系数的定义以及假定的状态方程必须将包括哈姆罗克和道森公式在内的经典公式的使用限制在具有高牛顿极限的液体和低温情况下。鉴于这个问题至少已经存在了五十年仍未得到解决，合理的结论是，不存在一种压力 - 粘度系数的定义能够量化高于环境温度时EHL膜厚解析计算中的压粘响应。
